High frequency composite component

ABSTRACT

A high-frequency composite component for selectively switching a GSM-system signal path and a DCS-system signal path for a signal transmitted to or received from an antenna terminal by a diplexer. Transmission-side input terminals and reception-side balanced output terminals to be switched by high-frequency switches are included in the GSM and the DCS systems. Matching elements include inductors and capacitors that are inserted between the reception-side balanced output terminals and the output side of surface acoustic wave filters.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a high-frequency composite component,and more particularly, to a high-frequency composite component for usein a plurality of different mobile communication systems.

2. Description of the Related Art

Presently, in Europe, as a mobile communication device, a dual-bandportable telephone has been proposed which can operate in a plurality offrequency bands, for example, in the DCS system using a 1.8 GHz band andthe GSM system using a 900 MHz band.

FIG. 18 shows a portion of the structure of a general dual-band portabletelephone which includes an antenna 1, a diplexer 2, and two signalpaths of a DCS system 3 (1.8 GHz band) and a GSM system 4 (900 MHzband).

The diplexer 2 selects a transmission signal from the DCS system 3 orthe GSM system 4 in transmission and selects a reception signal to theDCS system 3 or the GSM system 4 in reception. The DCS system 3 includesa high-frequency switch 3 a for separating a transmission portion Txdand a reception portion Rxd and a filter 3 b for allowing thefundamental frequency of the DCS system to pass through and forattenuating the second and third harmonics. In the same manner, the GSMsystem 4 also includes a high-frequency switch 4 a for separating atransmission portion Txg and a reception portion Rxg and a filter 4 bfor allowing the fundamental frequency of the GSM system to pass throughand for attenuating the third harmonics.

In recent years, a balanced-type (balanced-output type) high-frequencycomposite component having two signal terminals in the reception portionhas been proposed and, in such a balanced type, the impedance matchingto a low-noise amplifier (LNA) is required.

In Japanese Unexamined Patent Application Publication No. 2003-142981(Patent Document 1), as shown in FIG. 19, an inductor 6 is disposed inparallel between the balanced output terminals Rx of a bandpass filterdefined by a balanced-output type surface acoustic wave filter. However,it is difficult to set a desired impedance (complex impedance, inparticular). According to the knowledge of the present inventor, inorder to lower the impedance, a capacitor must be inserted in series toeach of the balanced output terminals, and, to increase the impedance,one more inductor must be inserted in parallel between the balancedoutput terminals in addition to the above-described capacitors. However,when capacitors and inductors as separate components are added betweensuch a high-frequency composite component and an LNA, the number ofcomponents and the mounting area increase which increases the size ofthe equipment, and the matching between the bandpass filter 5 and theLNA becomes more complicated.

SUMMARY OF THE INVENTION

To overcome the problems described above, preferred embodiments of thepresent invention provide a high-frequency composite component in whicha desired impedance is easily set in the high-frequency compositecomponent itself, no matching adjustment to an LNA is required, thenumber of components is reduced, and the overall size is reduced.

Furthermore, preferred embodiments of the present invention provide ahigh-frequency composite component in which interference between theelements is prevented, and in which excellent characteristics areachieved.

A high-frequency composite component according to a preferred embodimentof the present invention includes a switch for selectively switching asignal path between an antenna terminal and a transmission-side inputterminal and a signal path between the antenna terminal and areception-side balanced output terminal, an LC filter having an inductorand capacitors disposed between the antenna terminal and thetransmission-side input terminal, a surface acoustic wave filterdisposed between the switch and the reception-side balanced outputterminal, and a matching element having an inductor and capacitorsdisposed between the surface acoustic wave filter and the reception-sidebalanced output terminal. In the high-frequency composite component, theswitch, the LC filter, the surface acoustic wave filter, and thematching element are integrated in an integrated block having aplurality of laminated dielectric layers.

In the high-frequency composite component according to this preferredembodiment of the present invention, since a matching element having aninductor and capacitors is disposed between a surface acoustic wavefilter and a reception-side balanced output terminal, it is possible tofreely set the impedance of the reception-side balanced output terminalby an appropriate combination of the inductor and the capacitors.Moreover, since the inductor and the capacitors are integrated in alaminated block with other circuit components, as compared to where theinductor and the capacitors are discretely arranged on a printed-circuitboard, the mounting area on the printed-circuit board is reduced, thedistance between the surface acoustic wave filter and the matchingelement is minimized, and the loss between the filter and the matchingelement is suppressed to improve high-frequency characteristics.

An important consideration when the switch, the LC filter, the surfaceacoustic wave filter, and the matching element are integrated in alaminated block having a plurality of dielectric layers laminated is toarrange the components such that interference between the matchingelement and the LC filter is prevented. In particular, regarding theinductance of the matching element, a high Q value and stability arerequired.

In a high-frequency composite component according to this preferredembodiment of the present invention, it is desirable that the inductorof the matching element be disposed in a first area of the laminatedblock, and that the inductor and the capacitors of the LC filter bedisposed in a second area different from the first area as viewed fromthe top.

In the same manner, it is desirable that the inductor of the matchingelement be disposed on the surface of the laminated block and that theinductor and the capacitors of the LC filter be disposed inside thelaminated block. Furthermore, it is desirable that a ground electrode bedisposed between the inductor of the matching element and the inductorand the capacitors of the LC filter. Alternatively, it is desirable thata shunt capacitor of the capacitors of the LC filter be disposed in thevicinity of the lowest layer of the laminated block.

The inductor and the capacitors of the matching element are disposed onthe surface of the laminated block, and the inductor of the matchingelement may be disposed so as to be directly next to the capacitors ofthe matching element with no other elements disposed therebetween.

Furthermore, the surface acoustic wave filter may be a balanced-typesurface acoustic wave filter having balanced output ports or the surfaceacoustic wave filter may be an unbalanced-type surface acoustic wavefilter having unbalanced output ports. When the surface acoustic wavefilter is a balanced-type filter, the inductor of the matching elementis connected in parallel between the balanced output ports, and thecapacitors of the matching element are connected in series to thebalanced output ports. Furthermore, when the surface acoustic wavefilter is an unbalanced-type filter, the inductor and the capacitors ofthe matching element function as a balun.

Moreover, a high-frequency composite component according to a preferredembodiment of the present invention is a high-frequency compositecomponent of a dual-band type in which signals in two differentfrequency bands can be processed. In such a high-frequency compositecomponent of a dual-band type, a diplexer for branching a signal pathfor a first frequency band and a signal path for a second frequency banddifferent from the first frequency band is provided at the rear stage ofthe antenna terminal. In the signal path for a first frequency band, afirst switch for selectively switching a signal path between the antennaterminal and a first transmission-side input terminal and a signal pathbetween the antenna terminal and a first reception-side balanced outputterminal, a first LC filter having an inductor and capacitors disposedbetween the first switch and the first transmission-side input terminal,a first surface acoustic wave filter disposed between the first switchand the first reception-side balanced output terminal, and a firstmatching element having an inductor and capacitors disposed between thefirst surface acoustic wave filter and the first reception-side balancedoutput terminal are provided. In the signal path for a second frequencyband, a second switch for selectively switching a signal path betweenthe antenna terminal and a second transmission-side input terminal and asignal path between the antenna terminal and a second reception-sidebalanced output terminal, a second LC filter having inductors andcapacitors disposed between the second switch and the secondtransmission-side input terminal, a second surface acoustic wave filterdisposed between the second switch and the second reception-sidebalanced output terminal, and a second matching element having aninductor and capacitors disposed between the second surface acousticwave filter and the second reception-side balanced output terminal areprovided. The diplexer, the first and second switches, the first andsecond LC filters, the first and second surface acoustic wave filters,and the first and second matching elements are integrated in a laminatedblock having a plurality of laminated dielectric layers.

A high-frequency composite component according to another preferredembodiment of the present invention is a high-frequency compositecomponent of a triple-band type in which signals in three differentfrequency bands can be processed. In such a high-frequency compositecomponent of a triple-band type, a diplexer for branching a signal pathfor a first frequency band and a signal path for a second frequency banddifferent from the first frequency band is provided at the rear stage ofthe antenna terminal. In the signal path for a first frequency band, afirst switch for selectively switching a signal path between the antennaterminal and a first transmission-side input terminal and a signal pathbetween the antenna terminal and a first reception-side balanced outputterminal, a first LC filter having an inductor and capacitors disposedbetween the first switch and the first transmission-side input terminal,a first surface acoustic wave filter disposed between the first switchand the first reception-side balanced output terminal, and a firstmatching element having an inductor and capacitors disposed between thefirst surface acoustic wave filter and the first reception-side balancedoutput terminal are provided. In the signal path for a second frequencyband, a second switch for selectively switching a signal path betweenthe antenna terminal and a second transmission-side input terminal and asignal path between the antenna terminal and second and thirdreception-side balanced output terminals, a second LC filter havinginductors and capacitors disposed between the second switch and thesecond transmission-side input terminal, a duplexer branching a signalpath disposed between the second switch and the second reception-sidebalanced output terminal and a signal path disposed between the secondswitch and the third reception-side balanced output terminal, a secondsurface acoustic wave filter disposed between the duplexer and thesecond reception-side balanced output terminal, a second matchingelement having an inductor and capacitors disposed between the secondsurface acoustic wave filter and the second reception-side balancedoutput terminal, a third surface acoustic wave filter disposed betweenthe duplexer and the third reception-side balanced output terminal, anda third matching element having an inductor and capacitors disposedbetween the third surface acoustic wave filter and the thirdreception-side balanced output terminal are provided. The diplexer, thefirst and second switches, the first and second LC filters, the first,second, and third surface acoustic wave filters, and the first, second,and third matching elements are integrated in a laminated block having aplurality of laminated dielectric layers.

Other features, elements, steps, characteristics and advantages of thepresent invention will become more apparent from the following detaileddescription of preferred embodiments of the present invention withreference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing the basic structure of a firstpreferred embodiment of a high-frequency composite component accordingto the present invention.

FIG. 2 is an equivalent circuit diagram of the first preferredembodiment.

FIG. 3 is a block diagram showing the basic structure of a secondpreferred embodiment of a high-frequency composite component of thepresent invention.

FIG. 4 is an equivalent circuit diagram of the second preferredembodiment.

FIG. 5 is a schematic illustration showing the shape of electrodesprovided on each sheet layer (first to eighth layers from the bottom) ofa ceramic multilayer substrate of the second preferred embodiment.

FIG. 6 is a schematic illustration showing the shape of electrodesprovided on each sheet layer (ninth to fifteenth layers from the bottom)of a ceramic multilayer substrate of the second preferred embodiment.

FIG. 7 is a schematic illustration showing the shape of electrodesprovided on each sheet layer (sixteenth and seventeenth layers from thebottom) of a ceramic multilayer substrate of the second preferredembodiment.

FIG. 8 is a top view showing the mounting state of each circuit elementon the surface of the ceramic multilayer substrate of the secondpreferred embodiment.

FIG. 9 is a block diagram showing the basic structure of a thirdpreferred embodiment of a high-frequency composite component accordingto the present invention.

FIG. 10 is an equivalent circuit diagram of the third preferredembodiment.

FIG. 11 is an equivalent circuit diagram of a fourth preferredembodiment of a high-frequency composite component according to thepresent invention.

FIG. 12 is a schematic illustration showing the shape of electrodesprovided on each sheet layer (first to eighth layers from the bottom) ofa ceramic multilayer substrate of the fourth preferred embodiment.

FIG. 13 is a schematic illustration showing the shape of electrodesprovided on each sheet layer (ninth to fifteenth layers from the bottom)of a ceramic multilayer substrate of the fourth preferred embodiment.

FIG. 14 is a schematic illustration showing the shape of electrodesprovided on each sheet layer (sixteenth and seventeenth layers from thebottom) of a ceramic multilayer substrate of the fourth preferredembodiment.

FIG. 15 is a top view showing the mounting state of each circuit elementon the surface of the ceramic multilayer substrate of the fourthpreferred embodiment.

FIG. 16 is an equivalent circuit diagram of a fifth preferred embodimentof a high-frequency composite component according to the presentinvention.

FIG. 17 is an equivalent circuit diagram of a sixth preferred embodimentof a high-frequency composite component according to the presentinvention.

FIG. 18 is a block diagram showing a switching circuit of a relateddual-band portable telephone.

FIG. 19 is a block diagram showing the outline of the structure of arelated bandpass filter.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Hereinafter, the preferred embodiments of a high-frequency compositecomponent according to the present invention are described withreference to the accompanied drawings.

First Preferred Embodiment (FIGS. 1 and 2)

In a high-frequency composite component of a single-band type accordingto the first preferred embodiment, as shown in a block diagram of FIG.1, an inductor L is connected in parallel between the balanced outputportion of a balanced-typed surface acoustic wave filter SAW and thereception-side balanced output terminal Rx, and capacitors Cl and C2 areconnected in series, respectively.

In detail, as shown in an equivalent circuit diagram of FIG. 2, thehigh-frequency composite component includes a high-frequency switch 11,an LC filter 12, a balanced-type surface acoustic wave filter SAW, and amatching element 13.

The high-frequency switch 11 is for selectively switching a signal pathbetween an antenna terminal ANT and a transmission-side input terminalTx and a signal path between the antenna terminal ANT and areception-side balanced output terminal Rx. The LC filter 12 is disposedbetween the high-frequency switch 11 and the transmission-side inputterminal Tx and is a low-pass filter including an inductor GLt1 andcapacitors. The capacitors of the low-pass filter include a capacitor GCconnected in parallel to the inductor GLt1 and two grounding capacitors(shunt capacitors) GCu1 and GCu2 connected to the ground.

In the matching element 13, as described above, the inductor L isconnected in parallel and the capacitors C1 and C2 are connected inseries, respectively, between the balanced output portion of the surfaceacoustic wave filter SAW and the reception-side balanced output terminalRx.

Furthermore, in the first preferred embodiment, the above-describedhigh-frequency switch 11, LC filter 12, surface acoustic wave filterSAW, and matching element 13 are integrated in a laminated block inwhich a plurality of dielectric layers are laminated.

The high-frequency composite component according to the first preferredembodiment, which is a single-band type, is included in high-frequencycomposite components of second and third preferred embodiments of adual-band type and a high-frequency composite component of a fourthpreferred embodiment of a triple-band type as a component thereof.Accordingly, the more detailed structure and operation of the firstpreferred embodiment are disclosed with reference to the second, third,fourth, fifth, and sixth preferred embodiments to be described later.

Second Preferred Embodiment (FIGS. 3 to 8)

A high-frequency composite component according to the second preferredembodiment is a high-frequency composite component (front-end module) ofa dual-band type having GSM and DCS systems, as shown in a block diagramin FIG. 3. Inductors Lg and Ld are connected in parallel between thebalanced output portions of balanced-type surface acoustic wave filtersSAWg and SAWd and reception-side balanced output terminals Rxg and Rxd,and capacitors C1 g and C2 g, and C1 d and C2 d are connected in series,respectively.

In detail, as shown in an equivalent circuit diagram of FIG. 4, thehigh-frequency composite component includes a diplexer 20 for branchinga GSM-system signal path and a DCS-system signal path at the rear stageof the antenna terminal ANT. Moreover, the GSM system includes a firsthigh-frequency switch 11G, a first LC filter 12G, the firstbalanced-type surface acoustic wave filter SAWg, and a first matchingelement 13G. In the same manner, the CS system also includes a secondhigh-frequency switch 11D, a second LC filter 12D, the secondbalanced-type surface acoustic wave filter SAWd, and a second matchingelement 13D.

The first high-frequency switch 11G selectively switches a signal pathbetween the antenna terminal ANT and a first transmission-side inputterminal Txg and a signal path between the antenna terminal ANT and afirst reception-side balanced output terminal Rxg. The first LC filter12G is disposed between the first high-frequency switch 11G and thefirst transmission-side input terminal Txg. The first surface acousticwave filter SAWg is disposed between the first high-frequency switch 11Gand the first reception-side balanced output terminal Rxg.

In the first matching element 13G, the inductor Lg is connected inparallel on the side of the first surface acoustic wave filter SAWg, andthe capacitors C1 g and C2 g are connected in series between theinductor Lg and the reception-side balanced output terminal Rxg,respectively.

The second high-frequency switch 11D selectively switches a signal pathbetween the antenna terminal ANT and a second transmission-side inputterminal Txd and a signal path between the antenna terminal ANT and asecond reception-side balanced output terminal Rxd. The second LC filter12D is disposed between the second high-frequency switch 11D and thesecond transmission-side input terminal Txd. The second surface acousticwave filter SAWd is disposed between the second high-frequency switch11D and the second reception-side balanced output terminal Rxd.

In the second matching element 13D, an inductor Ld is connected inparallel on the side of the second surface acoustic wave filter SAWd,and the capacitors C1 d and C2 d are connected in series between theinductor Ld and the reception-side balanced output terminal Rxd,respectively.

The diplexer 20 selects a transmission signal from the DCS system or theGSM system during transmission and selects a reception signal to the DCSsystem or the GSM system during reception. The antenna terminal ANT isconnected to a first port P11 of the diplexer 20, the first port P31 gof the first high-frequency switch 11G is connected to a second portP12, and the first port P31 d of the second high-frequency switch 11D isconnected to a third port P13.

In the GSM system, a first port P21 g of the first LC filter 12G isconnected to a second port P32 g of the first high-frequency switch 11G,and the first surface acoustic wave filter SAWg is connected to a thirdport P33 g. The first transmission-side input terminal Txg is connectedto a second port P22 g of the first LC filter 12G.

In the DCS system, a first port P21 d of the second LC filter 12D isconnected to a second port P32 d of the second high-frequency switch11D, and the second surface acoustic wave filter SAWd is connected to athird port P33 d. The transmission-side second input terminal Txd isconnected to a second port P22 d of the second LC filter 12D.

The diplexer 20 includes inductors Lt1 and Lt2, and capacitors Cc1, Cc2,Ct1, Ct2, and Cu1. A parallel circuit defined by the inductor Lt1 andthe capacitor Ct1 is connected between the first port P11 and the secondport P12, and the side of the second port P12 of the parallel circuit isgrounded through the capacitor Cu1. Furthermore, the capacitors Cc1 andCc2 are connected in series between the first port P11 and the thirdport P13, and the connection point between them is grounded through theinductor Lt2 and the capacitor Ct2.

The first high-frequency switch 11G includes diodes GD1 and GD2 asswitching elements, inductors GSL1 and GSL2, capacitors GC5 and GC6, anda resistor RG. The diode GD1 is connected between the first port P31 gand the second port P32 g such that the anode is on the side of thefirst port P31 g, and the cathode is grounded through the inductor GSL1.The cathode of the diode GD2 is connected to the first port P31 gthrough the inductor GSL2, and the anode is grounded through thecapacitor GC5. A control terminal Vc1 is connected to the connectionpoint between the diode GD2 and the capacitor GC5 through the resistorRG. Furthermore, the connection point between the cathode of the diodeGD2 and the third port P33 g is grounded through the capacitor GC6.

The second high-frequency switch 11D includes diodes DD1 and DD2 asswitching elements, inductors DSL1, DSL2, and DSLt, capacitors DC6, DC7,and DCt1, and a resistor RD. The diode DD1 is connected between thefirst port P31 d and the second port P32 d such that the anode is on theside of the first port P31 d, and the cathode is grounded through theinductor DSL1. Furthermore, a series circuit of the capacitor DCt1 andthe inductor DSLt is connected in parallel to the diode DD1 between thefirst port P31 d and the second port P32 d. The cathode of the diode DD2is connected to the first port P31 d through the inductor DSL2, and theanode is grounded through the capacitor DC5. A control terminal Vc2 isconnected to the connection point between the diode DD2 and thecapacitor DC5 through the resistor RD. Furthermore, the cathode of thediode DD2 is connected to the third port P33 d through the capacitorDC6, and the connection point between the cathode and the capacitor DC6is grounded through the capacitor DC7.

In the first LC filter 12G, a parallel circuit of an inductor GLt1 and acapacitor GCc1 is connected between the first port P21 g and the secondport P22 g. Both ends of the inductor GLt1 are grounded throughcapacitors GCu1 and GCu2, respectively.

In the second LC filter 12D, a parallel circuit of an inductor DLt1 anda capacitor DCc1 and a parallel circuit of an inductor DLt2 and acapacitor DCc2 are connected in series between the first port P21 d andthe second port P22 d. Both ends of the inductor DLt1 are groundedthrough capacitors DCu1 and DCc2, respectively.

FIGS. 5 to 7 show capacitor electrodes and strip line electrodes formedby screen printing or other suitable method, on each sheet layerdefining a ceramic multilayer substrate of a high-frequency compositecomponent according to the second preferred embodiment. The ceramicmultilayer substrate is formed such that first to seventeenth sheetlayers 61 a to 61 q made of ceramics having barium oxide, aluminumoxide, and silica as main components are laminated in order from thebottom and sintered at a temperature of about 1000° C. or less.

Various terminal electrodes for external connection are provided on thefirst sheet layer 61 a. A ground electrode G1 is provided on the secondsheet layer 61 b, the electrodes for the capacitors GCu1, GCu2, Ct2, andGC5 are provided on the third sheet layer 61 c to define capacitancestogether with the ground electrode G1. A ground electrode G2 is providedon the fourth sheet layer 61 d, and the electrodes for the capacitorsDCu1 and DCu2 are provided on the fifth sheet layer 61 e to definecapacitances with the ground electrode G2.

The inductors Lt1, Lt2, DLt1, DLt2, GLt1, DSL1, and DSL2 are defined bystripline electrodes on the seventh and ninth sheet layers 61 g and 61 iand are connected by via holes. Moreover, the inductors Lt1, Lt2, DLt1,DLt2, GLt1, and DSL2 are defined by stripline electrodes on the eleventhsheet layer 61 k and are connected to the same electrodes on the lowerlayers by via holes.

The electrodes of the capacitors Ct1 and DCc1 are provided on the twelvesheet layer 611, and the electrodes of the capacitors Ct1, Cc1, DCt1,and GCc1 and the ground electrode G3 are provided. The electrodes of thecapacitors Cc1, DCt1, GCc1, and DC5 are provided on the fourteenth sheetlayer 61 n. The electrodes of the capacitors Cc2 and DCt1 and the groundelectrode G4 are provided on the fifteenth sheet layer 61 o.

As shown in FIG. 8, various connection terminal electrodes are providedon the surface of the seventeenth sheet layer 61 q defining the surfaceof the ceramic multilayer substrate 50. Then, on the surface, the firstand second surface acoustic wave filters SAWg and SAWd and the diodesGD1, GD2, DD1, and DD2 are mounted, and the inductor Lg and thecapacitors C1 g and C2 g defining the first matching element 13G and theinductor Ld and the capacitors C1 d and C2 d defining the secondmatching element 13D are mounted. Moreover, the resistors RG and RD andthe inductors DSL1, DSLt, and GSL1 are mounted on the surface of theceramic multilayer substrate 50.

Here, the operation of the high-frequency composite component having thecircuit structure shown in FIG. 4 is described. First, when atransmission signal of the DCS system (1.8 MHz band) is sent, in thesecond high-frequency switch 11D, the transmission signal of the DCSsystem passes through the second LC filter 12D, the secondhigh-frequency switch 11D, and the diplexer 20 and is transmitted fromthe antenna terminal ANT connected to the first port P11 of the diplexer20 such that, for example, about 3 V is applied to the control terminalVc2 to turn on the diodes DD1 and DD2.

At this time, in the first high-frequency switch 11G of the GSM system,the transmission signal of the GSM system is not transmitted such that,for example, 0 V is applied to the control terminal Vc1 to turn off thediode GD1. Furthermore, the transmission signal of the DCS system doesnot enter the first transmission-side input terminal Txg and the firstreception-side balanced output terminal Rxg of the GSM system due to theconnection of the diplexer 20. Moreover, the second and third harmonicsof the DCS system are attenuated in the second LC filter 12D of the DCSsystem.

Next, when a transmission signal of the GSM system (900 MHz band) issent, in the first high-frequency switch 11G, the transmission signal ofthe GSM system passes through the first LC filter 12G, the firsthigh-frequency switch 11G, and the diplexer 20 and is transmitted fromthe antenna terminal ANT connected to the first port P11 of the diplexer20 such that, for example, about 3 V is applied to the control terminalVc1 to turn on the diodes GD1 and GD2.

At this time, in the second high-frequency switch 11D of the DCS system,the transmission signal is not transmitted such that, for example, 0 Vis applied to the control terminal Vc2 to turn off the diode DD1.Furthermore, the transmission signal of the GSM system does not enterthe second transmission-side input terminal Txd and the secondreception-side balanced output terminal Rxd of the DCS system due to theconnection of the duplexer 20.

Moreover, the second harmonic of the GSM system is attenuated in thelow-pass filter made up of the capacitor Ct1, the inductor Lt1, and theshunt capacitor Cu1 of the diplexer 20 and the third harmonic of the GSMsystem is attenuated in the first LC filter 12G of the GSM system.

Next, when reception signals of the DCS system and the GSM system arereceived, in the second high-frequency switch 11D of the DCS system, areception signal of the DCS system does not enter the secondtransmission-side input terminal Txd such that, for example, 0 V isapplied to the control terminal Vc2 to turn off the diodes DD1 and DD2,and in the first high-frequency switch 11G of the GSM system, areception signal of the GSM system does not enter the firsttransmission-side input terminal Txg of the GSM system such that 0 V isapplied to the control terminal Vc1 to turn off the diodes GD1 and GD2.Then, the signals input from the antenna terminal ANT are output to thereception-side balanced output terminal Rxd of the DCS system and thereception-side balanced output terminal Rxg of the GSM system,respectively.

Furthermore, the reception signal of the DCS system does not enter theGSM system and the reception signal of the GSM system does not enter theDCS system due to the connection of the diplexer 20.

In the high-frequency composite component according to the secondpreferred embodiment, since the matching elements 13G and 13D includingthe inductors Lg and Ld and the capacitors C1 g, C2 g, C1 d, and C2 dare disposed between the surface acoustic wave filters SAWg and SAWd andthe reception-side balanced output terminals Rxg and Rxd, it is possibleto freely set the impedance of the reception-side balanced outputterminals Rxg and Rxd by appropriate combinations of the inductors andcapacitors.

Furthermore, since the inductors Lg and Ld and the capacitors C1 g, C2g, C1 d, and C2 d are integrated in the ceramic laminated substratetogether with the other circuit components, as comparison to when suchinductors and capacitors are discretely disposed on a printed circuitboard, the mounting surface on the printed substrate is reduced andsimultaneously the distance between the surface acoustic wave filtersSAWg and SAWd and the matching elements 13G and 13D is minimized so asto suppress the loss between the filters SAWg and SAWd and the matchingelements 13G and 13D and improve the high-frequency characteristics.

Furthermore, since the inductors Lg and Ld of the matching elements 13Gand 13D are arranged so as not to overlap with the inductors andcapacitors of the LC filters 12G and 12D in the ceramic laminatedsubstrate as seen from the top, the isolation between the transmissionand reception lines is secured and the mixture of a signal is prevented.Since the inductors Lg and Ld of the matching elements 13G and 13D aremounted on the surface of the ceramic laminated substrate, the sameeffect is attained by the inductors and capacitors of the LC filters 12Gand 12D being disposed inside the ceramic laminated substrate.

Moreover, in the present preferred embodiment, the capacitors C1 g, C2g, C1 d, and C2 d of the matching elements 13G and 13D are arranged soas not to overlap with the inductors and capacitors of the LC filters12G and 12D as seen from the top. In this manner, the mixture of asignal between the transmission and reception lines is more effectivelyprevented.

Furthermore, since the ground electrode G4 is disposed between theinductors Lg and Ld of the matching elements 13G and 13D and theinductors and capacitors of the LC filters 12G and 12D, the interferencebetween these components is effectively prevented. In addition, sincethe capacitors of the LC filters 12G and 12D, that is, the shuntcapacitors GCu1, GCu2, DCu1, and DCu2, in particular, are disposed inthe vicinity of the lower layer of the ceramic laminated substrate, thesame effect is obtained. Since the inductors Lg and Ld and thecapacitors C1 g, Cg2, C1 d, and C2 d of the matching elements 13G and13D are disposed on the surface of the ceramic laminated substrate, andsince the inductors Lg and Ld of the matching elements 13G and 13D arearranged next to the capacitors C1 g, C2 g, C1 d, and C2 d of thematching elements 13G and 13D with no other elements disposedtherebetween, mutual interference is effectively prevented.

Moreover, in the present preferred embodiment, the ground electrode G4is also disposed between the capacitors C1 g, C2 g, C1 d, and C2 d andthe inductors capacitors of the LC filters 12G and 12D. Thus, theinterference between these components effectively prevented.

Furthermore, as shown in FIG. 8, on the surface of the ceramicmultilayer substrate, the surface mounting components defining thematching elements 13G and 13D are disposed so as to be next to thesurface mounting components defining the high-frequency switches 11G and11D and the diplexer 20 through the surface acoustic wave filters SAWgand SAWd. With such an arrangement, the interference between thematching elements 13G and 13D and the other elements is more effectivelysuppressed.

Third Preferred Embodiment (FIGS. 9 and 10)

A high-frequency composite component according to a third preferredembodiment is a dual-band type high-frequency composite component havingGSM and DCS systems similar to the second preferred embodiment. As shownin a block diagram in FIG. 9, the capacitors C1 g and C2 g, and Cd andC2 d are connected in series to the balanced output portions of thebalanced-type surface acoustic wave filters SAWg and SAWd, and theinductors Lg and Ld are connected in parallel to the reception-sidebalanced output terminals Rxg and RXd.

Thus, the impedance of the first and second reception-side balancedoutput terminals Rxg and Rxd can be freely set and the impedance can beincreased, in particular, such that the capacitors C1 g and C2 g and thecapacitors C1 d and C2 d are connected in series to the side of thefirst and second surface acoustic wave filters SAWg and SAWd, and theinductors Lg and Ld are connected in parallel to the side of the firstand second reception-side balanced output terminals Rxg and Rxd,respectively.

Moreover, in the third preferred embodiment, the circuit structure andoperation, except for the first and second matching elements 13G and13D, are the same as in the second preferred embodiment and theoverlapping description is omitted.

Fourth Preferred Embodiment (FIGS. 11 to 15)

A high-frequency composite component according to a fourth preferredembodiment is a triple-band type high-frequency composite componenthaving a GSM system and a DCS system branching off into tworeception-side balanced output terminals Rxd1 and Rxd2, as shown in anequivalent circuit diagram of FIG. 11.

That is, the GSM system includes a first high-frequency switch 11G, afirst LC filter 12G, a balanced-type first acoustic wave filter SAWg,and a first matching element 13G. The structure and operation of the GSMsystem is the same as that in the above-described second and thirdpreferred embodiments and the overlapping description is omitted.

The diplexer 20 also includes substantially the same structure as thatin the second and third preferred embodiments and, in addition, acapacitor Cant is connected between the first port P11 and the antennaterminal ANT, and the connection point is grounded through an inductorLant.

The DCS system includes a second high-frequency switch 11D′, a second LCfilter 12D, and a second transmission-side input terminal Txd. Thecircuit structure of this portion is the same as that in the second andthird preferred embodiments and the overlapping description is omitted.

In the DCS system, the third port P33 d of the second high-frequencyswitch 11D′ is connected to a duplexer 14D, and the duplexer 14Dbranches the path of a reception signal into a second reception-sidebalanced output terminal Rxd1 and a third reception-side balanced outputterminal Rxd2.

The second high-frequency switch 11D′ selectively switches a signal pathbetween the antenna terminal ANT and the second transmission-side inputterminal Txd and a signal path between the antenna terminal ANT and thesecond and third reception-side balanced output terminals Rxd1 and Rxd2.

The second high-frequency switch 11D′ includes the diodes DD1, and DD2as switching elements, inductors DPSL1, DSL2, and DPSLt, capacitors DC5,DC6, DPCt, and a resistor DR1. The diode DD1 is connected between thefirst port P31 d and the second port P32 d such that the anode is on theside of the second port P32 d, and the anode is grounded through theinductor DPSL1 and the capacitor DC6. The control terminal Vc2 isconnected to the connection point between the inductor DPSL1 and thecapacitor DC6. Furthermore, a series circuit of the capacitor DPCt andthe inductor DPSLt is connected between the first port P31 d and thesecond port P32 d so as to be parallel to the diode DD. The anode of thediode DD2 is connected to the first port P31 d through the inductorDSL2, and the cathode is grounded through the capacitor DC5. Theconnection point between the diode DD2 and the capacitor DC5 is groundedthrough the DR1.

In the duplexer 14D, an inductor PSL2 is connected between a first portP41 d and a second port P42 d, and the connection point between theinductor PSL2 and the second port P42 d is grounded through a capacitorPC7. The second port P42 d is connected to a second surface acousticwave filter SAWd1. Furthermore, a capacitor DC7 is connected between thefirst port P41 d and a third port P43 d of the duplexer 14D. Theconnection point between the capacitor DC7 and the first port P41 d isgrounded through a capacitor Cj, and simultaneously, the connectionpoint between the capacitor DC7 and the third port P43 d is groundedthrough the inductor DSL1.

A second matching element 13D1 is connected to the balanced outputportion of the second surface acoustic wave filter SAWd1, and a thirdmatching element 13D2 is connected to the balanced output portion of athird surface acoustic wave filter SAWd2. In the second and thirdmatching elements 13D1 and 13D2, in the same manner as in the secondpreferred embodiment, the inductors Ld are connected in parallel on theside of the surface acoustic wave filters SAWd1 and SAWd2, and thecapacitors C2 d and C2 d are connected in series between the inductorsLd and the reception-side balanced output terminals Rxd1 and Rxd2,respectively. The operation-effect is the same as in the secondpreferred embodiment. Moreover, the second and third matching elements13D1 and 13D2 may have the same circuit structure as in the thirdpreferred embodiment, and in this case, the same operation effect isobtained as in the third preferred embodiment.

FIGS. 12 to 14 show the capacitor electrodes and stripline electrodesformed by a screen printing or other suitable method, on each sheetlayer defining the ceramic multilayer substrate of a high-frequencycomposite component according to the fourth preferred embodiment.

Various external connection terminal electrodes are provided on thefirst sheet layer 62 a. A ground electrode G11 is provided on the secondsheet layer 62 b, and the electrodes of capacitors Cu1, Ct2, and DC6 areprovided on the third sheet layer 62 c to define a capacitance togetherwith the ground electrode G11. A ground electrode G12 is provided on thefourth sheet layer 62 d, and the electrodes of capacitors DCu1, DCu2,Cj, GCu1, and GCu2 are provided on the fifth sheet layer 62 e to definea capacitance together with the ground electrode G12.

The inductors Lt1, Lt2, DLt1, DLt2, GLt1, GSL2, DSL2, and PSL2 areprovided on the eight sheet layer 62 h using stripline electrodes.Inductors GSL2 and Lt1 are provided on the ninth sheet layer 62 i usingstripline electrodes and connected to the electrodes on lower layersthrough via holes.

The inductors Lt1, Lt2, DLt1, DLt2, GLt1, GSL2, DSL2, and DSL2 areprovided on the tenth sheet layer 62 j using stripline electrodes andconnected to the electrodes of the same kind on lower layers through viaholes. Inductors Lt1 and GSL2 are provided on the eleventh sheet layer62 k using stripline electrodes and connected to the electrodes of thesame kind on lower layers through via holes.

The inductors Lt2, DLt1, DLt2, GLt1, GSL2, and DSL2 are provided on thetwelve sheet layer 621 using stripline electrodes and connected to theelectrodes of the same kind on lower layers through via holes. Theelectrodes of the capacitors Ct1 and DCc2 are provided on the thirteenthsheet layer 62 m, and the electrodes of the capacitors Ct1 and Cc1 andthe ground electrode G13 are provided on the fourteenth sheet layer 62n. The electrodes of the capacitors DC5, Ct1, Cc1, GCc1, GC5, DCu1, andDCc2 are provided on the fifteenth sheet layer 62 o. The electrodes ofthe capacitors Cc2 and CCc1 and a ground electrode G14 are provided onthe sixteenth sheet layer 62 p. The electrodes of the capacitor DCc1 areprovided on the seventeenth sheet layer 62 q.

The surface of the nineteenth sheet layer 62 s is the surface of theceramic multilayer substrate 50, as is shown in FIG. 15, and variousconnection terminal electrodes are provided and the first to thirdsurface acoustic wave filters SAWg, SAWd1, and SAWd2 and the diodes GD1,GD2, DD1, and DD2 are mounted thereon. Moreover, the inductor Lg and thecapacitors C1 g and C2 g defining the first matching element 13G and theinductor Ld and the capacitors C1 d and C2 d defining the second andthird matching elements 13D1 and 13D2 are mounted thereon.

Moreover, on the surface of the ceramic multilayer substrate 50, theresistors RG and DR1 are mounted, the inductors Lant, DPCt, DPSLt, DSL1,and DPSL1 are mounted, and the capacitors Cant, DC7, and PC7 aremounted.

In the high-frequency composite according to the fourth preferredembodiment, a reception signal can be switched to the secondreception-side balanced output terminal Rxd1 and the thirdreception-side balanced output terminal Rxd2 by turning on and off thediode of the second high-frequency switch 11D′. The other basicoperations are the same as described in the second preferred embodimentand the operation effect is also the same as in the second preferredembodiment.

In particular, as shown in FIG. 15, on the surface of the ceramicmultilayer substrate, the surface mounting components defining thematching elements 13G, 13D1, and 13D2 are disposed so as to be oppositeto the surface mounting components defining the high-frequency switches11G and 11D′, the diplexer 20, and the duplexer 14D through the surfaceacoustic wave filters SAWg, SAWd1, and SAWd2. Such an arrangementfurther suppresses the interference between the matching elements 13G,13D1, and 13D2 and the other elements.

Fifth Preferred Embodiment (FIG. 16)

A high-frequency composite component according to a fifth preferredembodiment is a triple-band type, as shown in an equivalent circuit ofFIG. 16. The structure is basically the same as that of the fourthpreferred embodiment (see FIG. 11) and the operation effect is also thesame as the fourth preferred embodiment. The different between the fifthpreferred embodiment and the fourth preferred embodiment is that thereception-side balanced output terminals Rxd1 and Rxd2 are separated bya diode switch 15D, instead of by the duplexer 14D.

The diode switch 15D includes diodes SDD1 and SDD2 as switchingelements, inductors SID1 and SID2, capacitors SC1, SC2, and SC3, and aresistor SR. A first port P51 d is connected to the third port P33 d ofthe second high-frequency switch 11D′, and the other end of thecapacitor SC3, one end of which is connected to the first port P51 d, isconnected to the anode of the diode SDD2 through the cathode of thediode SDD1 and the inductor SID2.

The anode of the diode SDD1 is grounded through the inductor SID1 andthe capacitor SC1, and a control terminal Vc3 is connected to theconnection point between the inductor SID1 and the capacitor SC1. Thecathode of the diode SDD2 is grounded through the capacitor SC2, and theconnection point between the cathode and the capacitor SC2 is groundedthrough the resistor SR. The second port P52 d connected to the anode ofthe diode SDD1 is connected to the second surface acoustic wave filterSAWd1. Furthermore, the third port P53 d connected to the anode of thediode SDD2 is connected to the third surface acoustic wave filter SAWd2.

Sixth Preferred Embodiment (FIG. 17)

A high-frequency composite component according to the sixth preferredembodiment is a triple-band type high-frequency composite component, asshown in FIG. 17. The structure is basically the same as that of thefourth preferred embodiment (see FIG. 11) and the operation effect isalso the same as in the fourth preferred embodiment. The difference isthat the surface acoustic wave filters SAWd1 and SAWd2 having unbalancedoutput ports are of an unbalanced type and the matching elements 13D1and 13D2 connected to the unbalanced output ports are defined as baluns.

Other Embodiments

Moreover, the high-frequency composite components according to thepresent invention are not limited to the above-described embodiments,and various modifications can be made without departing from the spiritand the scope of the invention.

For example, in the above-described preferred embodiments,high-frequency composite components of a single-band type, a dual-bandtype, and a triple-band type were described, but the present inventioncan be also applied to high-frequency composite components of anymulti-band type, such as a quad-band type.

Furthermore, in the above-described preferred embodiments, although theLC filters 12, 12G, and 12D for attenuating higher-order harmonics aredisposed between the high-frequency switches are 11, 11G, 11D, and 11D′and the transmission-side input terminals Tx, Txg, and Tsd, they may bedisposed between the antenna terminal ANT (diplexer 20) and thehigh-frequency switch.

As described above, the present invention is useful for a high-frequencycomposite component which can be utilized in a plurality of differentmobile communication systems and, in particular, is advantageous becausea desired impedance can be easily set and no matching adjustment to LNAsis required.

While preferred embodiments of the present invention have been describedabove, it is to be understood that variations and modifications will beapparent to those skilled in the art without departing the scope andspirit of the present invention. The scope of the present invention,therefore, is to be determined solely by the following claims.

1-10. (canceled)
 11. A high-frequency composite component comprising: aswitch for selectively switching a signal path between an antennaterminal and a transmission-side input terminal and a signal pathbetween the antenna and a reception-side balanced output terminal; an LCfilter including an inductor and capacitors disposed between the antennaterminal and the transmission-side input terminal; a surface acousticwave filter disposed between the switch and the reception-side balancedoutput terminal; and a matching element including an inductor andcapacitors disposed between the surface acoustic wave filter and thereception-side balanced output terminal; wherein the switch, the LCfilter, the surface acoustic wave filter, and the matching element areintegrated in a laminated block including a plurality of laminateddielectric layers.
 12. A high-frequency composite component according toclaim 11, wherein the inductor of the matching element is disposed in afirst area of the laminated block, and the inductor and the capacitorsof the LC filter are disposed in a second area different from the firstarea as viewed from above the laminated block.
 13. A high-frequencycomposite component according to claim 11, wherein the inductor of thematching element is mounted on the surface of the laminated block, andthe inductor and the capacitors of the LC filter are disposed inside thelaminated block.
 14. A high-frequency composite component according toclaim 11, wherein a ground electrode is disposed between the inductor ofthe matching element and the inductor and the capacitors of the LCfilter.
 15. A high-frequency composite component according to claim 11,wherein a shunt capacitor of the capacitors of the LC filter is disposedin the vicinity of the lowermost layer of the laminated block.
 16. Ahigh-frequency composite component according to claim 11, wherein theinductor and the capacitors of the matching element are provided on thesurface of the laminated block, and the inductor of the matching elementis disposed so as to be directly next to the capacitors of the matchingelement with no other element therebetween.
 17. A high-frequencycomposite component according to claim 11, wherein the surface acousticwave filter is a balanced-type surface acoustic wave filter havingbalanced output ports, the inductor of the matching element is connectedin parallel between the balanced output ports, and the capacitors of thematching element are connected in series to the balanced output ports.18. A high-frequency composite component according to claim 11, whereinthe surface acoustic wave filter is an unbalanced-type surface acousticwave filter having unbalanced output ports, and the inductor and thecapacitors of the matching element define a balun.
 19. A high-frequencycomposite component according to claim 11, wherein the inductor of thematching element does not overlap with the inductor and the capacitorsof the LC filter as viewed from above the laminated block.
 20. Ahigh-frequency composite component comprising: an antenna terminalincluding a rear stage; a diplexer disposed at a rear stage of theantenna terminal that branches a signal path for a first frequency bandand a signal path for a second frequency band different from the firstfrequency band; in the signal path for a first frequency band, a firstswitch for selectively switching a signal path between the antennaterminal and a first transmission-side input terminal and a signal pathbetween the antenna terminal and a first reception-side balanced outputterminal, a first LC filter having an inductor and capacitors disposedbetween the first switch and the first transmission-side input terminal,a first surface acoustic wave filter disposed between the first switchand the first reception-side balanced output terminal, and a firstmatching element having an inductor and capacitors disposed between thefirst surface acoustic wave filter and the reception-side balancedoutput terminal; in the signal path for a second frequency band, asecond switch for selectively switching a signal path between theantenna terminal and a second transmission-side input terminal and asignal path between the antenna terminal and a second reception-sidebalanced output terminal, a second LC filter having inductors andcapacitors disposed between the second switch and the secondtransmission-side input terminal, a second surface acoustic wave filterdisposed between the second switch and the second reception-sidebalanced output terminal, and a second matching element having aninductor and capacitors disposed between the second surface acousticwave filter and the second reception-side balanced output terminal areprovided; wherein the diplexer, the first and second switches, the firstand second LC filters, the first and second surface acoustic wavefilters, and the first and second matching elements are integrated in alaminated block including a plurality of laminated dielectric layers.21. A high-frequency composite component comprising: an antennaincluding a rear stage; a diplexer disposed at the rear stage of theantenna terminal that branches a signal path for a first frequency bandand a signal path for a second frequency band different from the firstfrequency band; in the signal path for a first frequency band, a firstswitch for selectively switching a signal path between the antennaterminal and a first transmission-side input terminal and a signal pathbetween the antenna terminal and a first reception-side balanced outputterminal, a first LC filter having an inductor and capacitors disposedbetween the first switch and the first transmission-side input terminal,a first surface acoustic wave filter disposed between the first switchand the first reception-side balanced output terminal, and a firstmatching element having an inductor and capacitors disposed between thefirst surface acoustic wave filter and the first reception-side balancedoutput terminal; in the signal path for a second frequency band, asecond switch for selectively switching a signal path between theantenna terminal and a second transmission-side input terminal and asignal path between the antenna terminal and second and thirdreception-side balanced output terminals, a second LC filter havinginductors and capacitors disposed between the second switch and thesecond transmission-side input terminal, a duplexer branching a signalpath disposed between the second switch and the second reception-sidebalanced output terminal and a signal path disposed between the secondswitch and the third reception-side balanced output terminal, a secondsurface acoustic wave filter disposed between the duplexer and thesecond reception-side balanced output terminal, a second matchingelement having an inductor and capacitors disposed between the secondsurface acoustic wave filter and the second reception-side balancedoutput terminal, a third surface acoustic wave filter disposed betweenthe duplexer and the third reception-side balanced output terminal, anda third matching element having an inductor and capacitors disposedbetween the third surface acoustic wave filter and the thirdreception-side balanced output terminal; wherein the diplexer, the firstand second switches, the first and second LC filters, the first, second,and third surface acoustic wave filters, and the first, second, andthird matching elements are integrated in a laminated block including aplurality of laminated dielectric layers.
 22. A high-frequency compositecomponent comprising: a switch for selectively switching a signal pathbetween an antenna terminal and a transmission-side input terminal and asignal path between the antenna and a reception-side balanced outputterminal; an LC filter disposed between the antenna terminal and thetransmission-side input terminal; a surface acoustic wave filterdisposed between the switch and the reception-side balanced outputterminal; and a matching element disposed between the surface acousticwave filter and the reception-side balanced output terminal; wherein theswitch, the LC filter, the surface acoustic wave filter, and thematching element are integrated in a laminated block including aplurality of laminated dielectric layers.
 23. A high-frequency compositecomponent according to claim 22, wherein the matching element includesan inductor and a plurality of capacitors, and the LC filter includes aninductor and a plurality of capacitors.
 24. A high-frequency compositecomponent according to claim 23, wherein the inductor of the matchingelement is disposed in a first area of the laminated block, and theinductor and the plurality of capacitors of the LC filter are disposedin a second area different from the first area as viewed from above thelaminated block.
 25. A high-frequency composite component according toclaim 23, wherein the inductor of the matching element is mounted on thesurface of the laminated block, and the inductor and the plurality ofcapacitors of the LC filter are disposed inside the laminated block. 26.A high-frequency composite component according to claim 23, wherein aground electrode is disposed between the inductor of the matchingelement and the inductor and the plurality of capacitors of the LCfilter.
 27. A high-frequency composite component according to claim 23,wherein a shunt capacitor of the plurality of capacitors of the LCfilter is disposed in the vicinity of the lowermost layer of thelaminated block.
 28. A high-frequency composite component according toclaim 23, wherein the inductor and the plurality of capacitors of thematching element are provided on the surface of the laminated block, andthe inductor of the matching element is disposed so as to be directlynext to the plurality of capacitors of the matching element with noother element therebetween.
 29. A high-frequency composite componentaccording to claim 23, wherein the surface acoustic wave filter is abalanced-type surface acoustic wave filter having balanced output ports,the inductor of the matching element is connected in parallel betweenthe balanced output ports, and the plurality of capacitors of thematching element are connected in series to the balanced output ports.30. A high-frequency composite component according to claim 23, whereinthe surface acoustic wave filter is an unbalanced-type surface acousticwave filter having unbalanced output ports, and the inductor and theplurality of capacitors of the matching element define a balun.
 31. Ahigh-frequency composite component according to claim 23, wherein theinductor of the matching element does not overlap with the inductor andthe plurality of capacitors of the LC filter as viewed from above thelaminated block.